题解 | #汽水瓶#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
       while(in.hasNextLine()) {
        int input = in.nextInt();
        if (input == 0) {
            break;
        }

        int totalwater=0;
        int ping=input;

        while(ping>0) {
            if (ping < 2) {
                break;
            }
            if (ping == 2) {
                totalwater++;
                break;
            }

            ping-=3;
            totalwater++;
            ping++;
        }
        
        System.out.println(totalwater);


       }
    }
}